The roots of the Inquisition go back to the 11th and 12th centuries, when various dissident groups began springing up in Catholic Europe. But the Inquisition proper was inaugurated by Pope Lucius III at the Synod of Verona, Italy, in 1184. In collaboration with Holy Roman Emperor Frederick I Barbarossa, he decreed that any person who spoke or even thought contrary to Catholic doctrine would be excommunicated by the church and duly punished by the secular authorities. Bishops were instructed to seek out (Latin, inquirere) heretics. This was the beginning of what was called the Episcopal Inquisition, that is, placed under the authority of the Catholic bishops.

Thus, for a time, there were two parallel Inquisitions, called the Episcopal and the Legatine Inquisitions, the latter more severe than the former.